


Iridescent

by inoreuct



Series: Of Warriors and Angels [3]
Category: Haikyuu!!
Genre: Alternate Universe - Mythology, Angst, Angst and Fluff, Angst with a Happy Ending, Blood, Explorer!Daichi, Fantasy, Fluff, Happy Ending, M/M, Mermaids, Mythology - Freeform, daisuga - Freeform, mermaid au, mermaid!suga, mythological creatures, shark attacks
Language: English
Status: Completed
Published: 2020-10-14
Updated: 2020-10-19
Packaged: 2021-03-08 21:55:00
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, No Archive Warnings Apply
Chapters: 4
Words: 6,978
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27003904
Author URL: https://archiveofourown.org/users/inoreuct/pseuds/inoreuct
Summary: What happens when an explorer gets shipwrecked in uncharted waters and a merman saves him?
Relationships: Sawamura Daichi/Sugawara Koushi
Series: Of Warriors and Angels [3]
Series URL: https://archiveofourown.org/series/1969135
Comments: 19
Kudos: 76





	1. Man Overboard

Sawamura Daichi knew what he was getting into the minute he unfurled the sails on his schooner and set course for the South Pacific Sea. He knew that he would be sailing straight into uncharted waters, and that those waters were uncharted because they were choppy and dangerous. He just didn’t think that they would be _this_ dangerous. His precious sailboat was being tossed around on the waves like a child’s toy, and water was spilling all over the deck. The skies were grey and completely blanketed by thick, heavy storm clouds, and rain was pouring down in torrents. Any hope that Daichi had previously about the moon giving him good visibility was quashed. To add insult to injury, the winds were ferocious, the gales sharp and cutting like whips across skin. Daichi was soaked to the bone, so cold he couldn’t feel his arms or legs, his teeth chattering uncontrollably. The sudden storm had caught him completely unprepared, and lightning cracked across the sky as thunder boomed loud and threatening in the explorer’s ears. He looked up to the masts of his ship, where delicate pieces of soaked cloth were being blown around like leaves in a hurricane. _Fuck. I need to get the sails down before they rip._

Daichi tried not to dwell on the direness of his current situation, because if he did, he would give up trying to survive through the night, and he owed it to his parents and family to at least try and get back home alive. He stabilised the steering wheel and tied its spokes in place with a random length of rope that he (thankfully) had the wits to grab before his world descended into chaos, and ran to the bottom of the main mast to hoist the sails. He had the rope in his hands and was pulling it frantically, but there was one thing he had forgotten to take into account; the rocky islands floating around everywhere. With the rain and the lack of illumination except the occasional streak of lightning, Daichi could barely see his hand in front of his face. So when a flash of lightning lit up the sky and revealed the looming silhouette of a chunk of rock right in front of his boat, he dashed for the steering wheel, but he knew that it was too late. Spinning the wheel as far to the left as it could go, the explorer narrowly avoided a head-on collision, but he felt the floating island bash into the side of his boat, and he was fairly sure that it had smashed a hole in the hull from the sound of wood splintering. 

_Come on, come on…_ He squinted in front of him, planting his feet firmly on the slick wooden deck when he spotted a relatively clear patch of water. However, he must have overturned the steering wheel, because Daichi felt something huge smash into the left side of his boat, and suddenly he was slipping, sliding straight down across the wet wooden deck of his horizontally-tilting schooner. He scrabbled frantically at the wet wood, trying to catch himself, but his hands and leather-clad feet couldn’t find purchase. He started turning around, sliding backwards upside down on his back while struggling to right himself, but he must have bashed his head into the railing, for he soon found himself in a pitch-black sea with stars sparking behind his eyelids. 

Daichi thrashed in the dark water, trying to get his bearings, but the world was spinning around and around and _around_ and he couldn’t tell which way was up. He couldn’t see a thing. It was so dark he might as well have been swimming in ink; who knew? He could have been. These were uncharted waters, after all. Daichi’s lungs were starting to burn, and he still couldn’t tell if he was swimming deeper into the water or towards the surface. All of a sudden, he felt something latch onto his wrist and tried to yank it back, but the _thing_ tightened its grip. _What the… Is that a hand?!_ Fingers, _human_ fingers, so pale they seemed to glow in the darkness were clutching his arm. _Oh god… Reanimated corpse? Some sea monster?_ Daichi shuddered when he felt something like fish scales brush against his ankles and the hand tugged him closer, but he was too weak to fight back. The last thing he saw was a glint of silver before he passed out.


	2. Silver Scales

**Summary for the Chapter:**

> Vicious or just misunderstood?

Daichi’s eyes fluttered open, before he snapped them shut against the glare of the sun. He groaned, throwing an arm over his eyes; his head was pounding something fierce. From the cold water that was lapping at his legs and the smell of wet stone, he guessed that he was in some sort of cave. His head was resting on something firm but not hard, kind of like... _someone’s thigh?_ He tried to sit up, and he could feel somebody helping, a cool palm supporting the back of his neck. Slowly cracking open his eyes, squinting in the light, he caught sight of a flash of silver-white scales, the same ones that he saw the previous night. As his eyes adjusted to the glare and he could open his eyes fully, he could feel somebody’s arm supporting his back, and a silky tail was curled around his folded legs. _Wait… Tail?_ His first instinct was to scramble away, but the _thing_ that was holding him let out a musical chirp, obviously trying to calm him. 

Daichi looked over his shoulder. The _thing_ in question was a boy, no, a _man,_ with soft-looking silver hair and skin that gleamed like mother-of-pearl, luminous and crystalline. His arms and torso were lean and toned, and where his legs were supposed to be was a silvery-white fish tail, covered in holographic scales. _A mermaid_ was the first thing Daichi thought. _...He’s beautiful_ was the second. But then he remembered the stories his parents told him. They were marine folklorists that had dedicated their lives to learning the myths and legends of the seven seas. When Daichi was a child, his bedtime stories had been filled with fantasy and adventure, with krakens and giant squids and most prominently, mermaids. According to his parents, they were vicious creatures. Beautiful, yes, but vicious, monsters with hidden fangs and claws, who lured humans with their ethereal looks and dragged them underwater to their deaths and ate them. The mangled bodies on the seabed were proof.

But judging from the silver scales, this man had saved Daichi the previous night. _Why would he save me if he wants to eat me?_ The man chirped softly again, and Daichi, now slightly less wary, asked, “What happened?” 

The mermaid smiled, his tail sweeping across the wet floor. “Ah, so you’re Japanese. I should have guessed.” 

Daichi stared. “How do you know how to speak Japanese?” 

“Well, let’s just say that it’s a perk that comes with being a sea spirit.” The merman smiled good-naturedly, shrugging his shoulders. 

“...You saved me last night, didn’t you?” 

“...Yeah. You hit your head pretty hard, it was bleeding.” Daichi reached up to his forehead and his fingers pressed against something wet and slimy. He pulled it away and looked at the chunk of dark green seaweed in his hand. Lifting his fingers again, he ran them over his hairline and felt an raised patch of skin that felt suspiciously like a healed-over gash. 

“Ah, looks like it’s healed, but you probably still have a pretty bad concussion, don’t you? I’m Sugawara, by the way. Sugawara Koushi. But you can call me Suga.” 

Daichi looked away from the merman. That smile was dangerous; too pretty. He cleared his throat. “Y-Yeah, it’s pounding pretty bad. I’m Sawamura Daichi.” 

Suga hummed thoughtfully, absentmindedly swishing his tail through the shallow layer of water on the stone floor of the cavernous cave they were in, surrounding the solitary dry patch that they were both sitting on. “Well, in that case, we should wait until you’re totally okay before we get you back onland. I’m strong, but still not strong enough to swim an unconscious person all the way to shore.” He slid into the water and inched himself towards the edge of the cave, where the stone floor slowly fell away to the open ocean, turning around to shoot Daichi a quick smile. “I’m gonna go get food. Stay here, alright?”

Daichi tried to get up, but his head started spinning again. “Wait!” His plea was futile. Suga had already tipped himself headfirst into the water and was gone with a flick of his shimmering tail fin.

Daichi sighed. _Does he even know what humans eat? What if he brings me a fish?_ He looked around the cave, taking in the wet walls and the water on the floor. _No way I’ll be able to start a fire in here, the air’s too damp. Where am I, anyway?_ From what Suga had said before, he guessed that the cave was pretty far away from the coast. _And why’s he helping me? Isn’t he supposed to be vicious or something?_

*

Before long, Suga had come back. Daichi could tell that he was towing something behind him in the water, something really big, and he silently prayed that the merman hadn’t brought him a dead dolphin or something even worse. But as Suga hoisted himself up into the cave with his arms and dragged whatever he had brought up too, Daichi was stunned. There, sitting a few feet away in a woven web of seaweed, were _oysters._ Huge, numerous, blessedly edible _oysters._ Seeing the astonished look on the dark-haired man’s face, Suga chuckled sheepishly. “I hope these are okay; I couldn’t find anything else that I thought you could eat. Even the seaweed around here would be too tough for you to chew.”

Daichi laughed in disbelief. “Did you get all of these yourself?”

Suga was silent for a moment. _What if he brings more humans to… I don’t know, fish or something?_ But the silver-haired merman had always been good at reading people, and he sensed no ill intent from Daichi. “Yeah. When you know the right places…” he trailed off, shrugging absentmindedly. Wiggling around in the shallow water, he pushed the net towards the dark-haired man, handing him a sharp, flat rock. “Use that to shuck them open.”

Daichi stared into Suga’s warm hazel eyes. “Suga… Why are you helping me? I’m incredibly grateful, but aren’t you supposed to be...I don’t know...vicious monsters who drown and eat...people…?” He wanted to take his words back as soon as they left his mouth, But Suga didn’t seem fazed, only curious and contemplative. 

“Is that really what you land-dwellers think of us?” Daichi nodded cautiously. “Well, we don’t eat humans. Or drown them. Those were the sharks that protect us.”

Daichi frowned, his mind racing. “Wait, so… No claws? Fangs?”

“Well… We admittedly do have those. But only for self-defense. The only times that humans have seen us were when we're trying not to get captured or killed. And as to why I’m helping you…” The merman’s brown eyes lightened to a shade that was almost gold, skipping like a stone on a smooth lake over Daichi’s features, and the explorer had the distinct impression that he was being X-rayed. “Your boat didn’t have any weapons, did it? You were unarmed. You didn’t want to hurt or capture any of us. Not like the others.” 

A shadow passed over Suga’s face, and Daichi had a sudden yearning to know more, to learn all that he could about the mysterious, beautiful creature sitting before him. But he could tell that Suga didn’t want to talk about what happened just then, so he reached for the net of oysters and grabbed one, sliding the sharp rock between the shells and popping it open. The oyster was obviously fresh and very healthy, the flesh plump and the inside of the shell lined with nacre. And sitting right there in the middle, glowing in the sunlight, was a pearl, lustrous and opaline. Daichi stared at it for a moment, before spinning it around in his palm and offering it to Suga. “For you.” The merman’s eyes went wide, his lips parting slightly in surprise, but he reached out and took the oyster all the same, slender fingers carefully picking out the pearl before he tipped the shell up and swallowed its contents whole. And that smile that he gave Daichi when he looked back up? That relaxed, lazy grin? It was worth so much more than that rare, precious pearl. 


	3. Smile for Me

**Summary for the Chapter:**

> How far would you swim for the one you love?

_A melodious laugh, hazel-brown eyes sparkling with mirth. The playful flap of a silky tail fin at his ankles, flicking water over his legs. Only fingers brushing, at first. Smiles softer and more intimate. Then, hands smoothing tentatively across hair, scales. Hands clutching at each other for comfort on chilly nights. Then cool skin pressing against his own, toned arms cradling him close as he pretended to be asleep. The soft press of plush lips against his nose, his forehead, his temples, his cheeks as he drifted off to dreamland, but never on his lips._

*

Daichi didn’t understand. According to the lines he carved onto the stone wall of the cave every day, it had been over a month since his ship had been smashed and Suga had saved him. Every night, Suga stayed nearby, either sleeping half-underwater, half curled around Daichi, his strong tail twined around his legs, or swimming around in the water just outside the cave, keeping watch and guarding the explorer from aquatic threats. Daichi had been sleeping on a blanket and pillow made of woven kelp (courtesy of Suga, of course), and surviving off rainwater and fresh oysters and clams that Suga brought to him on a daily basis. He constantly asked himself why the merman was doing this, and part of him hoped that it was because Suga reciprocated his rapidly growing feelings. He didn’t know if he _loved_ the merman, not when he had put romance and relationships aside in favour of exploring for his whole life, but he definitely felt _something_ for his silver-haired saviour. Something strong. But somewhere in the dark recesses of his mind, he vaguely wondered if he had some form of Stockholm Syndrome, because _Suga wouldn’t let him leave._ Not explicitly, but every time Daichi mentioned that he wanted to get back to shore, Suga would advise him to rest and wait a few more days. He knew that a month was more than enough time for his concussion to heal, and he felt perfectly fine; he had even taken to doing calisthenics around the cave to stay in shape. So _why wouldn’t Suga let him leave?_

Daichi didn’t want to go. He didn’t want to leave, didn’t want to break off the bond he had formed with this amazing creature. No, this amazing _person._ Suga had stopped being just a creature to Daichi a long time ago. Still, he knew that he had to leave at some point. He had no way of contacting his family, and he couldn’t let them believe that he was dead. The merman was blinking drowsily, his head resting on his folded arms, lying on his stomach in the shallow water. Daichi braced himself. “Suga. Why won’t you let me go?” 

The mermaid raised his head slowly, looking up at the dark-haired explorer. “Hmm?” 

Daichi frowned, his full brows furrowing together. “Every time I suggest leaving, you say that I should stay a little while longer.”

Suga sat up straighter. “I’m not-” 

“I have to get back, Sugawara. This has gone on long enough. I have a family, I need to go _home_ -” 

“ _This?_ What’s _this_?” Suga dragged himself up and folded his tail beneath him, staring hard at Daichi. His normally expressive brown eyes were unreadable.

“This… I don’t know, okay? All I know is that I need to get home.” Daichi looked away, unable to look into those beautiful eyes any longer.

Suga was silent for a long while. “...I don’t want you to go because when you do, I’ll be all alone.” He looked away too, his palms smoothing over his tail, a nervous habit Daichi realised he had. 

The explorer’s head snapped back towards him. “What-” 

“My parents died when I was just a child. They were caught and killed by fishermen, stabbed straight through their hearts with harpoons and dragged on deck.” Suga said matter-of-factly, his tone short, almost robotical. It obviously still hurt him to talk about the past. “Their boat crashed and broke apart on the rocks afterwards, _but I lost my family that day, Daichi._ I have no home. Nobody to go to. I was all alone, before you fell into the water right in front of me, like some sort of fallen angel, a warrior of the gods, dressed in your cotton tunic and leatherware. And now I’ll be alone again.” Daichi was too stunned to speak. Suga swallowed, turning around, and the explorer thought he saw a glimmer of tears catch the fading light of the setting sun. “I’m sorry. ...We’ll head for shore first thing at dawn tomorrow morning. I’m going to get dinner.” He swam towards the edge of the cave and with a flick of his tail, he was gone, the salt on his face washed away by the ocean. 

Over the course of a month, Daichi had needed Suga, and depended on him to survive. But he had never once considered that Suga needed him too. Scrambling to his feet, he waded into the shallow water in the cave, walking to the edge where he jumped into the ocean without hesitation, leaving the cave for the first time since a month ago. Once the rock was gone from beneath his feet, however, Daichi felt a flash of panic bolt through him; he hadn’t had the best experience with water the last time around, and it was taking him a while for his muscles to remember how to swim. Once he got the hang of it, he swum farther away from the cave, trying to look for the silver-haired merman. _Fuck. He went underwater. How am I supposed to find him now?_ With no other choice, Daichi took a deep breath. “Suga!” Silence. The water was eerily still compared to the waves that had tossed his boat around like a toy. He tried again. “SUGA!”

This time, Daichi felt water currents move around him as he treaded water, and Suga’s pale hair floated up next to him. “Daichi? What are you doing?!” 

He swam towards the merman, reaching out a hand to cup his face. “I’m sorry, I didn’t know-” His eyes widened when Suga grabbed his wrist, pulling him back to the cave.

“You have to get back to the cave, it’s not safe-” 

“Why? What-” 

“ _You don’t understand_ , it’s not _safe_ -” Suga whined, distressed, still tugging ungently on Daichi’s arm.

Daichi pulled his hand back, reaching for Suga’s cheek as the merman finally stopped swimming and turned around. “Then make me understand, Suga! I’m sorry…” He trailed off as he got a good look at his face. 

Suga was blanched, his expression flat-out terrified. Not for himself, but for _Daichi._ “ _Sharks._ We’re in great white territory right now. It’s not safe, you have to go back-” 

“What about you?” 

“They won’t hurt me, they’re supposed to protect mermaids, remember? But-” 

The sun had set fully by now, but even through the darkness of the water, it was easy to see the black shadow that passed under them. “ _Oh, fuck.”_ It was the first time Daichi had heard Suga swear; understandably, it made him panic, on top of the threat of being eaten by sharks. Only internally, though, because he refused to lose his cool, especially when Suga was already so distressed. He flinched when he felt sandpaper-rough skin brush against his ankles, looking down into the water to look for the threat, but it was too dark. And before either of them could react, razor teeth sank into Daichi’s calf, dragging him underwater and biting half of his lower leg clean off.

He didn’t feel anything at first. He just remembered not being able to move, holding his breath and floating in water that was steadily turning red with his blood. It all seemed unreal, hazy and distant, an out-of-body experience; the bloody stump where his right foot used to be, the cloud of crimson surrounding him, Suga tugging frantically at his arm and screaming something in his face, his silver hair tinted pink. Daichi blinked at him blankly; he couldn’t hear, couldn’t feel, couldn’t even move. “-ichi! Ple- -ave to swi- -Daich- you ha- swim! _You have to swim!_ ” 

And everything came rushing back. The pain, the _burning_ pain in his leg, the panic that sent his heart racing and his stomach twisting into knots. Suga’s frantic expression, his features twisted up in worry and fear and _pain_. The push and tug of water as the shark turned back around, ready to finish off its prey. Suga screamed in frustration, wrapping his arms around a limp Daichi’s chest under his arms and swimming to the surface as fast as he could, but he wasn’t fast enough. The shark had looped around behind them, charging straight from the left with its jaws wide open. Suga let go of Daichi just in time to get out of the way as his left arm disappeared into that deadly, gaping maw, knife-like teeth clamping over his chest. 

The shark was huge, and its teeth even more so. Daichi could feel them piercing his flesh, strong jaws crushing his rib cage. He couldn’t tell if those were teeth or his own splintered bones stabbing into his lungs; all he knew was that bolts of pain were shooting through his body as he spasmed in the water, and that he was going to die. _I’m dying._ Until he wasn’t. Someone was prying the shark’s jaws apart, their claws digging into its tough skin and dragging it back. Naturally, the shark let go of Daichi, leaving him with a ring of bloody punctures across his chest. 

When Daichi stopped twitching enough for his eyes to refocus, he saw Suga fighting the shark… But also not the Suga he knew. This Suga had curved claws instead of fingernails, ripping bloody streaks into the shark and shredding up its skin, and long, sharp fangs instead of teeth, bared as his face twisted in an animalistic snarl. And as Daichi watched, he pushed the shark’s jaws wide apart, all the way back until the crack and snap of cartilage was audible even through the water, and ripped the shark’s lower jaw clean off with his bare hands, a haze of blood surrounding him. Suga pushed the carcass away and spun back around to face Daichi, and the explorer was scared for a moment; the merman in front of him looked vengeful and wild, _demonic,_ with a cloud of blood blossoming behind him. But then the claws and fangs retracted, and it was _Suga_ ; the same Suga that had cared for Daichi for a month, the same Suga that Daichi loved (he was sure of his feelings now), the same Suga that maybe loved Daichi back. 

“No, no no no no no-“ Suga swam forward, his eyes travelling over Daichi’s mangled form. “No- _No!_ ” With his adapted lungs he could breathe just fine underwater, but he realised that Daichi must have been suffocating from the lack of oxygen. _Okay, okay, air. He needs air._ Suga wrapped shaky hands around the explorer’s waist, using his tail to push them upwards to shore. “Stay with me- Daichi, _stay with me!_ ” The dark-haired man coughed as they breached the surface, and Suga let out a small sigh of relief; at least he was breathing, still alive. _For now._ He laid Daichi flat on top of his arms and lifted them so that Daichi was above the water, and gave his tail a few warm-up flicks.

Suga swam. He swam for _miles_ without stopping, holding Daichi above the water with nothing but his arms, all the way until the shore was in sight, even though he specifically said that he wasn’t strong enough; and he didn’t lie, he was exhausted. Any longer and he would pass out, and Daichi could tell. From the heavy breathing, from the way Suga’s arms trembled, Daichi could tell. But Suga refused to stop. Daichi was bleeding out, and if Suga didn’t get him to shore soon, he would die, and the merman wasn’t going to let that happen. Not to mention that the blood might attract more sharks. 

Daichi had forced himself to stay awake even though he almost lost consciousness a couple of times, knowing that if his body shut down, he would never wake up again. He could feel Suga’s exhaustion, the trembling of his muscles, how he slowed down. _Maybe it’d be easier for him if I just died. He wouldn’t need to swim anymore. He could rest…_ He let his eyes slide closed, his head tipping back.

“Daichi. Daichi, don’t you dare. Stay with me, you hear? You need to go home. You need to get back to your family, just _stay with me,_ ” Suga pleaded, his voice raspy and breathless. Still, he opened his mouth, and the most beautiful sounds that Daichi had ever heard poured out (well, maybe with the exception of those two musical chirps that he had made when they first met), echoing through the water. Suga’s song settled over him like a blanket, warm and comforting in the cold ocean, trilled in a language that he didn’t understand but words he treasured all the same. 

“Suga-“ he coughed. His lungs were punctured and filling up with water and blood. His leg was bleeding out. He wouldn’t make it. “Suga, you have to let me go.” 

Suga popped up and shook his head vigorously, still singing the same melody over and over and over again, louder now that he wasn’t under the water. He pulled Daichi close to his chest, and a few tears dripped from his fine lashes. 

Daichi realised that he must have been crying since the shark had attacked. “You’re exhausted, and I’m not gonna make it. You have to let me go. You know that you c-can’t breathe underwater if your body is too tired, you’ll drown.” He raised his uninjured right arm, the back of his curled second finger swiping away the tears on Suga’s face that came fast and thick. 

Suga stopped singing as a choked sob wormed its way out of his throat. “No- No, Daichi, the shore’s right there, see? You’re gonna make it. _We’re_ gonna make it. Daichi- I can’t lose you too.” He whimpered again, his shoulders shuddering. “ _I can’t lose you too._ ” 

Daichi cupped his face in a shaky palm. The wounds all over his body had burned at first and the saltwater only made it worse, but now he just felt numb and tingly all over. “Y-You won’t- lose me,” he gasped. His lungs were filled with liquid now; he couldn’t breath and his time was running out, but he still had so much left to say. “You won’t lose me. I’ll always-“ he coughed, “be with you. Always. You have t-to let me go.” Suga wouldn’t stop crying, still trying to sing through his tears. “Please don’t cry. I want-“ he coughed again, “I want my last memory of you to be a happy one. S-Smile for me. Please.” Suga laughed, salty tears pouring over his luminescent cheeks before Daichi wiped them away again. 

The explorer closed his eyes, resting his head on the merman’s chest, recalling all his memories of the past month. He and Suga, splashing water and throwing oyster shells at each other. He and Suga, laughing over some dumb joke he had told. Suga, asleep with his head on Daichi’s lap, snoring gently. Suga, throwing his head back in a melodious laugh. Suga smiling. Suga being happy. Suga.

He opened his eyes and the merman was still there, desperately trying to keep smiling. Daichi traced fingers over his face one last time, over his smooth soft skin and those damned pink lips. “Thank you, Koushi,” he breathed, before gently pushing himself away from the merman, smiling softly when Suga didn’t try to stop him. He refused to say _I love you_ even though he knew, now, that he loved Suga more than anything, because he didn’t want to make their goodbye even more painful than it already was. It would only be cruel, to give Suga those words when they both knew that this was the end; they would never see each other again, not physically. Maybe in another time, another life, but not this one.

As Daichi sank down into the depths of the ocean, Suga’s agonised wail ripping through the water, his last thought before he lost consciousness was how beautiful Suga’s tail was above him, shimmering pink and purple and blue and a myriad of other holographic colours in the moonlit water, and how it paled in comparison to his smile. That one special smile, soft and sweet, the kind that Daichi liked to think you saved for the person you loved. _Iridescent_. He didn’t regret sacrificing himself to save Suga. He would never regret that. He only wished that he could have seen that iridescent smile one last time.

*

Suga didn’t know how long he’d been crying. Sharks were circling around him; they had smelled his tears and got worried about the creature they were supposed to protect, but Suga pushed them away when they came to nose at his tail. He knew that they meant well, but he didn’t know if he could look at another one of them the same way ever again, not after what they did to the man he loved. And oh, _god,_ did he love Daichi. Somehow, in thirty days, he had tumbled head over heels for the explorer. _And now he’s gone._ The merman was crying too hard into his hands to realise the water currents changing slightly as something rose up from the sea floor, taking in its new surroundings. He was too distressed to notice the shadow coming up behind him, the inky, metallic black scales, the strong, powerful tail that pushed the creature to the surface. Suga didn’t notice, not until a pair of arms were winding tight around his waist, hands flat across his abdomen. 

Suga knew those hands, _sailor’s_ hands, with their scars and calluses and imperfections; he knew that there was a scar on the top of the right second finger that had been caused by a piranha, and he knew that there was a small birthmark on the palm of the left hand. He had spent hours studying those hands when his explorer was asleep, and he knew them like he knew his own. Suga spun around, and a pair of warm, soft lips were on his, tasting like sea berries and sweetness, and he melted into a broad, tanned chest as a smooth, scaled tail twined tenderly with his own. He pulled back and stared into Daichi’s rich, dark brown eyes, filled with emotion and so much _love_ he thought that he must have been blind to have missed it before. 

“You’ll never be alone. Never. Not anymore.” Daichi pressed Suga to his chest, tucking the silver-haired merman’s face into his neck and dropping a kiss to his hair. “Not while I’m here.” 

“I thought- _How?_ You- you have a tail! It’s _beautiful_.” Suga looked over Daichi’s muscled shoulder to where his black tail was twined with his own silver one. No, not just black, but a whole slew of charcoal, gray and navy hues that blended to give an illusion of darkness. 

Daichi turned to press a kiss to Suga’s pale cheek. “Nowhere as beautiful as you.” 

Suga blushed a little. “Well, if you insist, but _how?_ ” 

Daichi hummed thoughtfully. “Well, the last thing I wished before I passed out was that I just wanted to see your smile again. A proper one. And when I woke up, I was buried in sand and silt, but I could breathe.” He pulled back to rest their foreheads together, rubbing Suga’s nose with his own. “And I had a tail, and my wounds were healed. So I dug my way out and swam up to you. And yes, I do insist. You are _beautiful_ , Koushi. And nothing else will ever compare. I’m never leaving your side; _you_ are my home now.”

Suga felt breathless like when he had swum all the way to shore in one go, but this time for a completely different reason. “But- Your parents? Your family?”

Daichi sighed gently. “We can figure that out later. I just want to stay with you. Wherever you go, I go.”

“Alright. If that’s what you want.”

“It is. Being with you, making you happy, you in general… That’s all I want.”

Suga grinned like a fool, whacking Daichi’s shoulder playfully. “Alright I get it, you love me. How’re you feeling?” (He had to joke, or he would’ve started crying like a baby from the sweetness overload.)

“Well, I can speak…pretty much every language I can think of. And I do love you.” He switched to Japanese. “Ai shiteru.” He switched to French. “Je t’aime.” He switched to German. “Ich liebe dich.” Then Italian, “Ti amo.” And then Spanish, “Te amo.”

And before he could make Suga really start crying, the silver merman interrupted him with the song he had been singing before, as he swam Daichi across the sea. And Daichi could _understand_ , Suga was singing _I love you, I love you, I love you,_ over and over and over again. 

  
And so Daichi parted his lips and sang back, the first words of an unfamiliar language on his tongue being _I love you, Sugawara Koushi._

**Notes for the Chapter:**

> Do y'all want an epilogue of domestic Daisuga life under the sea?


	4. Epilogue

“Suga? What’s wrong?” Daichi’s stomach was feeling more than a little twisty. His mate was biting his lip, flicking his tail frantically, his hands tightly gripping his upper arms. Just a few minutes before when Daichi had gotten home, he had been swimming around their little underwater cave in a panic, looking all over for something, and Daichi was pretty sure he knew what it was. He just didn’t think that it would cause Suga so much anxiety. 

“I-” The merman’s teeth sunk further into his lip, and he looked to the side as his mate got up from their seaweed nest and swam towards him, gently pulling his hands away from his arms. “I’m sorry, Dai, I- I think I lost the pearl you gave me. The day we met. I can’t find it, and I didn’t mean to, but-” He was cut off by a pair of soft, firm lips against his. 

Daichi felt something twist in his chest. “I’m sorry, I… I didn’t think you’d notice. I didn’t mean to make you upset.” He reached into the small satchel hung at his hip and pulled out a seashell, creamy white streaked vertically with pale pink and purple. He carefully opened it, and Suga gasped when he saw what was inside.

During the year that they had been together so far, Daichi had given Suga many beautiful pieces of jewellery; braided bracelets of kelp, delicate collars of colourful coral, strings upon strings of pearls. But _this_ … This beat them all. It was the pearl that Daichi had given him on the day they had met (yes, the one that he’d been stressing over), still raw and unpolished but beautiful, turned into a charm. It hung on a chain of… Suga didn’t even know what that _was_. It looked like silver, or maybe white gold, but it shimmered and refracted the light of the bioluminescence around them like a diamond. _That’s… There’s no way, it doesn’t exist. But it looks exactly like how the ancient texts described it…_ “Is that…?”

Daichi grinned sheepishly. “Adamantine. The-”

“-metal of the gods,” Suga finished for him, his eyes wide in wonder. 

“I know how much you wanted to see it after reading so much about it, so I asked Asahi for a favour. Turns out that one of his friends was off exploring and found a whole lot of it buried under the silt in the Atlantic, so I had him make a chain out of it and turn the pearl into a charm. I know how much you love his jewellery. I’m sorry that I made you anxious; I thought you wouldn’t notice that I took the pearl, and I wanted it to be a surprise. It was insensitive of me.”

Suga looked at his mate. The dark-haired merman’s head was bowed, his eyes lowered to the stone floor of their warm cave, the shell and necklace still extended between them like some sort of unnecessary olive branch. He gently took the shell from Daichi’s hands, lifting the necklace out carefully and passing it to his mate before he turned around. “Help me put it on?”

Daichi unclasped the fine chain, looping it over Suga’s head before fastening it again behind his neck. As his silver-haired mate turned around, he sighed gently, lips curving up in an awed smile despite the guilt still bubbling in the pit of his stomach. The pearl rested perfectly in the hollow of Suga’s throat, glowing in the light of the bioluminescent microorganisms that shared the waters of the deep sea with them. “Happy anniversary, Koushi.” 

“Happy anniversary, Daichi. And please don’t look so guilty, you’re making me feel bad! You look like a kicked puppy,” Suga giggled, gliding into his mate’s arms and rubbing his nose up the side of Daichi’s neck. 

The dark-haired merman gasped exaggeratedly. “I do _not_. ...But I made you stress. I can’t _not_ feel guilty.” 

Suga rested his chin on Daichi’s collarbone, looking up at the pouting merman. “Well, I kiss that pearl for good luck every morning and night when I do my skincare routine, and it was still there yesterday night, so you must have taken it just now before you went out. So you already tried to get the charm done in the shortest time. And to get it done in, what, barely two hours? With _adamantine,_ no less? That must have cost a fortune, Dai.”

Suga poked Daichi’s chest playfully. “I told you to stop wasting your sand dollars on me. And you made my gift pale in comparison!” He grabbed Daichi’s wrist and swam them to the corner where he had hidden a whole kelp-net full of oysters, dragging it out from behind their sofa. “Surprise!!!”

“Koushi… You spoil me.” Daichi pressed a kiss to the sensitive spot on Suga’s neck, right behind his jaw and below his ear. 

“You’re one to talk. You got me a necklace made with the rarest metal in the world! I don’t even want to know how much it cost, but _thank you._ It’s absolutely beautiful.”

“Not as much as you.”

“Oh, stop it. Are you seriously still going to say that when I’m old and grey?”

“You’re already grey- _ow!_ Okay, I’m sorry, I’m sorry-” Daichi laughed and squirmed as his mate karate-chopped his side with conviction. 

“ _Platinum!_ I’m _platinum_ , not _grey_! Hah! The atrocity- I should eat all these oysters myself!” Suga huffed, sticking his nose haughtily into the water and crossing his arms. 

Daichi laughed, wrapping his arms around the _platinum-_ haired merman again. “You’ll get sick like that, Koushi. The last time you threw up, it took the current _ages_ to carry away your puke.”

“Hey! Hmph. Now I’ll eat them all just to spite you-” Suga stuck his tongue out at Daichi with a small _bleh_ , his nose scrunching up adorably, before throwing himself down on their kelp nest and grabbing an oyster. Daichi could see the I’m-trying-not-to-grin-like-a-fool-but-failing-miserably look on his face, so he knew that his mate wasn’t actually upset. He flopped down next to Suga, rolling onto his back lazily, gazing up at the other merman. “Kou. Koushi, look at me.” His mate turned to him, an oyster in his hand, but he put it down when he saw the serious look on Daichi’s face. “I was serious. I will always call you beautiful, even when you’re old and grey. Because you’re _radiant_ , and your soul is evergreen. And even if it weren’t, I’d still call you beautiful, because you’ll always be beautiful to me.”

Suga smiled, a little sadly. “I‘ll be holding you to that when I get old and fat and ugly and you get tired of me.”

Daichi snorted, nuzzling his face into Suga’s side. “Please. If anyone gets old and fat and ugly first, it’d probably be me. And if I ever make you upset, if I ever say or do anything to hurt you, kick my ass.” He looked straight into Suga’s brown eyes, all traces of humour gone. “I’m serious. I’d deserve it. I love you, Sugawara Koushi. Old and grey or not.” He grabbed his mate’s hand that was resting on the woven seaweed, pressing a kiss to his knuckles. “Now gimme an oyster.”

Suga hummed, picking up the oyster he had previously put down and shucking it open with a sharp, flat rock. He pried the shell apart and hovered it over Daichi’s open mouth…

And swallowed it whole. Daichi yelped as the empty shell bounced off his forehead, letting out an affronted squawk of “ _betrayal!_ ”. 

Suga flicked his forehead, picking up another oyster. “Sit up and feed yourself, you big baby.” 

“But why would I feed myself when I have you- _ow!_ ”

**Notes for the Chapter:**

> JEWELLER ASAHI JEWELLER ASAHI JEWELLER ASAHI- okay, okay, I'll stop. BUT CANON. And just in case any of you were wondering, that friend who found the adamantine was Noya ;) (mmm, yes, totally just friends, but that's a story for another day ;))


End file.
